1. Field of the Invention
This invention relates to a load port apparatus which includes a lid member mounting and dismounting apparatus for mounting and dismounting a lid member on and from a carrier cassette, a mapping apparatus for carrying mapping and a plurality of lifting mechanisms for the lid member mounting and dismounting apparatus and the mapping apparatus, and a controlling method for the lifting mechanisms.
2. Description of the Related Art
A load port apparatus includes a cassette table, a lid member mounting and dismounting apparatus and a mapping apparatus as disclosed in Japanese Patent Laid-Open No. 2006-173510. The cassette table is disposed horizontally on a load port frame disposed vertically and is configured to receive a carrier cassette placed thereon. The lid member mounting and dismounting apparatus includes a lid member suction plate which in turn includes a locking and unlocking mechanism and a suction cup and is mounted for upward and downward movement on the load port frame in order to mount and dismount the lid member on and from an opening of the carrier cassette. The mapping apparatus includes a substrate detection sensor disposed for retracting movement from a detection position for a group of substrates opposed to the opening of the carrier cassette and a second lifting mechanism different from a first lifting mechanism for the lid member mounting and dismounting apparatus and operable to move the substrate detection sensor upwardly and downwardly so that the substrate detection sensor carries out mapping which is detection of presence or absence of a substrate on each shelf of the carrier cassette. The load port apparatus is removably attached to the outer side of a substrate processing apparatus such that it operates from the inner side of the substrate processing apparatus to take a substrate into and out of the carrier cassette.
It is to be noted that, in the load port apparatus of an object of the present invention, a carrier cassette called FOUP cassette which has an opening only on one side, that is, on the front side, thereof is used. Therefore, the carrier cassette is disposed with the opening thereof directed to the substrate processing apparatus side, and a lid member is detached from the carrier cassette by a lid member mounting and dismounting apparatus. Thereafter, mapping of substrates on the shelves of the carrier cassette is carried out by the mapping apparatus, and then the substrates are taken out one by one from the carrier cassette and processed in the substrate processing apparatus. Then, the substrates after processed are successively placed on the shelves of the carrier cassette through the opening of the carrier cassette, and then mapping of the substrates on the shelves is carried out by the mapping apparatus. Thereafter, the opening of the carrier cassette is closed up with the lid member by the lid member mounting and dismounting apparatus, and then the entire carrier cassette is transported to a next processing step.
In a load port apparatus which has lifting mechanisms independently of each other for the lid member mounting and dismounting apparatus and the mapping mechanism, if both apparatus are moved up or down at the same time, then they sometimes interfere with each other at individually particular portions thereof. Therefore, the lifting mechanisms for the different apparatus are rendered operative separately in time to avoid such interference. Where the lifting apparatus for the different apparatus are rendered operative separately, the total time period required for the operation of dismounting and mounting of the lid member from and on the carrier cassette and mapping of wafers in the carrier cassette is the sum of periods of time required for the upward and downward movements of the different apparatus. Therefore, where the lifting mechanisms for the different apparatus are rendered operative separately, the total time period mentioned is elongated.
In processing of substrates, dismounting and mounting of a lid member from and on a carrier cassette and mapping of the substrates are not operation originally required for processing of the substrates but are auxiliary or confirmatory operation required inevitably in order to carry out original processing operation. Therefore, it is demanded to minimize the time required for the dismounting and mounting operation and the mapping operation.